This invention relates to wire coiling machines. Wire coiling machine developments over the last several decades have enabled the coiling of smaller and smaller diameter wire as the products using such coils, e.g., heating elements, have become more and more sophisticated, such as for instrumentation. Coils must be of uniform structure from turn to turn, for controlled incremental resistance and heating, even though formed of wire as small in diameter as a human hair. Consequently, the inventions by the inventor herein have ranged from the coiler in U.S. Pat. No. 2,227,602 to those in U.S. Pat. Nos. 2,868,267, 3,401,557 and 4,208,896, 4,258,561, 4,561,278, and finally to that in U.S. Pat. No. 4,569,216. In patents such as U.S. Pat. No. 3,401,557, there is disclosed the use of flexible drive shafts and timing belts to drive the coiling rolls, enabling the machine to be capable of dependably coiling very fine wire.
In recent years, users of such wire coils have desired tandem coils, i.e., two wires coiled in twin arrangement, or even triple coils of three wires. Multiple wire coils are more energy effective, developing more heat per surface area than single wire coils. However, tandem coiling takes twice the power input to operate the coiling rolls, and triple coiling requires three times the power input.
Coil suppliers are required to make coils of wire varying in size between hairlike diameter, to form coils of small diameter, e.g., about 0.032 inch, to larger wire of a diameter of, e.g., 0.040 to 0.060 inch to form coils as of one inch in diameter. The very fine wire, difficult to see clearly without magnification lenses, is used for sophisticated instrumentation and the like, intermediate size wire and coils are used for electrical appliances such as stove burners and the like, while the larger diameter wire coils are used for such purposes as industrial heat treating furnaces. The power and coiling characteristics over this vast size range differ tremendously. Therefore, different coiling machines are employed to operate on these different sizes of wire, and even to accommodate the double and triple coils mentioned above.
It would be advantageous to have one coiler that could coil wire over the large size range encountered, and also coil tandem and triple wire stock. Moreover, the machine should preferably be rugged, simple and easy to set up and operate so as to be useful in various parts of the world, even in less technically developed countries.